Yes, think about it this way. Player joins a guild that he or she loves, and earns his/her own GP for said guild. This player doesn't like said guild anymore, thus realizing they should quit. Now, does that guild actually deserve the players hard work, no. Also, the player should not be allowed to keep it because they earned it for that guild, meaning it should stay with that guild while their in the guild. So, if the player quits, the guild should lose the GP and the player should lose the GP, thus starting the cycle all over.